NumberRangeFormatter.java
// © 2018 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
package com.ibm.icu.number;
import com.ibm.icu.text.UFormat;
import com.ibm.icu.util.ULocale;
import java.io.InvalidObjectException;
import java.util.Locale;
/**
* The main entrypoint to the formatting of ranges of numbers, including currencies and other units
* of measurement.
*
* <p>Usage example:
*
* <pre>
* NumberRangeFormatter.with()
* .identityFallback(RangeIdentityFallback.APPROXIMATELY_OR_SINGLE_VALUE)
* .numberFormatterFirst(NumberFormatter.with().unit(MeasureUnit.METER))
* .numberFormatterSecond(NumberFormatter.with().unit(MeasureUnit.KILOMETER))
* .locale(ULocale.UK)
* .formatRange(750, 1.2)
* .toString();
* // => "750 m - 1.2 km"
* </pre>
*
* <p>Like NumberFormatter, NumberRangeFormatter instances (i.e., LocalizedNumberRangeFormatter and
* UnlocalizedNumberRangeFormatter) are immutable and thread-safe. This API is based on the
* <em>fluent</em> design pattern popularized by libraries such as Google's Guava.
*
* @author sffc
* @stable ICU 63
* @see NumberFormatter
*/
public abstract class NumberRangeFormatter {
/**
* Defines how to merge fields that are identical across the range sign.
*
* @stable ICU 63
* @see NumberRangeFormatter
*/
public enum RangeCollapse {
/**
* Use locale data and heuristics to determine how much of the string to collapse. Could end
* up collapsing none, some, or all repeated pieces in a locale-sensitive way.
*
* <p>The heuristics used for this option are subject to change over time.
*
* @stable ICU 63
* @see NumberRangeFormatter
*/
AUTO,
/**
* Do not collapse any part of the number. Example: "3.2 thousand kilograms – 5.3 thousand
* kilograms"
*
* @stable ICU 63
* @see NumberRangeFormatter
*/
NONE,
/**
* Collapse the unit part of the number, but not the notation, if present. Example: "3.2
* thousand – 5.3 thousand kilograms"
*
* @stable ICU 63
* @see NumberRangeFormatter
*/
UNIT,
/**
* Collapse any field that is equal across the range sign. May introduce ambiguity on the
* magnitude of the number. Example: "3.2 – 5.3 thousand kilograms"
*
* @stable ICU 63
* @see NumberRangeFormatter
*/
ALL
}
/**
* Defines the behavior when the two numbers in the range are identical after rounding. To
* programmatically detect when the identity fallback is used, compare the lower and upper
* BigDecimals via FormattedNumber.
*
* @stable ICU 63
* @see NumberRangeFormatter
*/
public static enum RangeIdentityFallback {
/**
* Show the number as a single value rather than a range. Example: "$5"
*
* @stable ICU 63
* @see NumberRangeFormatter
*/
SINGLE_VALUE,
/**
* Show the number using a locale-sensitive approximation pattern. If the numbers were the
* same before rounding, show the single value. Example: "~$5" or "$5"
*
* @stable ICU 63
* @see NumberRangeFormatter
*/
APPROXIMATELY_OR_SINGLE_VALUE,
/**
* Show the number using a locale-sensitive approximation pattern. Use the range pattern
* always, even if the inputs are the same. Example: "~$5"
*
* @stable ICU 63
* @see NumberRangeFormatter
*/
APPROXIMATELY,
/**
* Show the number as the range of two equal values. Use the range pattern always, even if
* the inputs are the same. Example (with RangeCollapse.NONE): "$5 – $5"
*
* @stable ICU 63
* @see NumberRangeFormatter
*/
RANGE
}
/**
* Used in the result class FormattedNumberRange to indicate to the user whether the numbers
* formatted in the range were equal or not, and whether or not the identity fallback was
* applied.
*
* @stable ICU 63
* @see NumberRangeFormatter
*/
public static enum RangeIdentityResult {
/**
* Used to indicate that the two numbers in the range were equal, even before any rounding
* rules were applied.
*
* @stable ICU 63
* @see NumberRangeFormatter
*/
EQUAL_BEFORE_ROUNDING,
/**
* Used to indicate that the two numbers in the range were equal, but only after rounding
* rules were applied.
*
* @stable ICU 63
* @see NumberRangeFormatter
*/
EQUAL_AFTER_ROUNDING,
/**
* Used to indicate that the two numbers in the range were not equal, even after rounding
* rules were applied.
*
* @stable ICU 63
* @see NumberRangeFormatter
*/
NOT_EQUAL
}
/**
* Class for span fields in FormattedNumberRange.
*
* @stable ICU 69
*/
public static final class SpanField extends UFormat.SpanField {
private static final long serialVersionUID = 8750397196515368729L;
/**
* The concrete field used for spans in FormattedNumberRange.
*
* <p>Instances of NUMBER_RANGE_SPAN should have an associated value, the index within the
* input list that is represented by the span.
*
* @stable ICU 69
*/
public static final SpanField NUMBER_RANGE_SPAN = new SpanField("number-range-span");
private SpanField(String name) {
super(name);
}
/**
* Serialization method resolve instances to the constant NumberRangeFormatter.SpanField
* values
*
* @internal
* @deprecated This API is ICU internal only.
*/
@Deprecated
@Override
protected Object readResolve() throws InvalidObjectException {
if (this.getName().equals(NUMBER_RANGE_SPAN.getName())) return NUMBER_RANGE_SPAN;
throw new InvalidObjectException("An invalid object.");
}
}
private static final UnlocalizedNumberRangeFormatter BASE =
new UnlocalizedNumberRangeFormatter();
/**
* Call this method at the beginning of a NumberRangeFormatter fluent chain in which the locale
* is not currently known at the call site.
*
* @return An {@link UnlocalizedNumberRangeFormatter}, to be used for chaining.
* @stable ICU 63
*/
public static UnlocalizedNumberRangeFormatter with() {
return BASE;
}
/**
* Call this method at the beginning of a NumberRangeFormatter fluent chain in which the locale
* is known at the call site.
*
* @param locale The locale from which to load formats and symbols for number range formatting.
* @return A {@link LocalizedNumberRangeFormatter}, to be used for chaining.
* @stable ICU 63
*/
public static LocalizedNumberRangeFormatter withLocale(Locale locale) {
return BASE.locale(locale);
}
/**
* Call this method at the beginning of a NumberRangeFormatter fluent chain in which the locale
* is known at the call site.
*
* @param locale The locale from which to load formats and symbols for number range formatting.
* @return A {@link LocalizedNumberRangeFormatter}, to be used for chaining.
* @stable ICU 63
*/
public static LocalizedNumberRangeFormatter withLocale(ULocale locale) {
return BASE.locale(locale);
}
/** Private constructor - this class is not designed for instantiation */
private NumberRangeFormatter() {}
}